1. Field of the Invention
The present invention relates to a heat-sensitive recording material containing a diazonium salt and a coupler as color developing components, and more particularly to a heat-sensitive recording material, which suppresses green stains and has high background whiteness.
2. Description of the Related Art
A diazonium salt is generally a very chemically active compound, and reacts with a phenol derivative or a compound having an active methylene group, which is called a coupler, to easily form an azo dye. Also, the diazonium salt is photosensitive and, when irradiated with light, decomposes and loses activity.
Then, the diazonium salt is utilized as an optical recording material including a diazo-copying medium (for example, refer to xe2x80x9cBase of Photographic Technology-Non-Silver Salt Photograph Chapter-xe2x80x9d edited by Japan Photograph Society, Corona Publishing Co., Ltd. (1982), pp.89-117, pp.182-201). In recent years, the salt is also applied to recording materials for which fixation of an image is required. As a representative thereof, a light-fixing type heat-sensitive recording material having a recording layer which includes a diazonium salt and a coupler has been proposed. The heat-sensitive recording material is heated in accordance with image signals to react the diazonium salt and the coupler and to form an image, and then the image is fixed by light irradiation (for example, refer to Bulletin of Image Electronics Association, Hirotsugu Sato et al. vol. 11, No. 4 (1982), pp.290-296).
In a heat-sensitive recording material containing a diazonium salt compound and a coupler, various stains occur in certain cases. The hue of the stains is often yellow, but can also be green in certain cases.
Accordingly, there is a need for a heat-sensitive recording material in which green stains of the heat-sensitive recording material hardly occur.
In view of such a situation, the inventors of the invention have intensively studied, and, as a result, have found inclusion of an oxonol dye in a heat-sensitive recording material suppresses green stein and improves background whiteness, and have devised the invention.
The present invention provides a heat-sensitive recording material having a support and a heat-sensitive recording layer, which contains a diazonium salt compound and a coupler compound that reacts with the diazonium salt to develop a color, wherein the recording material contains an oxonol dye.